Variable responses of maize root architecture in elite cultivars due to soil compaction and moisture

Abstract

Crop genotypes may respond differently to various physical soil conditions. The objective of this study was to investigate the responses of the root architectures of two maize cultivars (Zhengdan958 and Denghai605) to various soil compaction and moisture conditions. Two compaction levels (1.3 g cm− 3 and 1.6 g cm− 3) and two moisture conditions (60% and 80% field capacity) were investigated to determine their impact on root growth. The root architectures of maize seedlings were assessed via X-ray computed tomography (CT). Soil penetration resistance, above-ground biomass and root biomass values were also determined. Soil moisture had significant effects on root biomass, above-ground biomass, the ratio of root biomass to above-ground biomass, and all root traits except for root volume. Soil compaction reduced root surface area and total root length of Zhengdan958 at 80% field capacity but not at 60% field capacity. However, soil compaction had little impact on root traits of Denghai605 at both moisture levels. Zhengdan958 had larger root volume, total root length, root diameter, root biomass and above-ground biomass than Denghai605 under noncompacted conditions. The ratio of root biomass to above-ground biomass was greater for Zhengdan958 than Denghai605 at the noncompacted and 60% field capacity conditions. High moisture content has negative effects on root traits in compacted soil. The response of root architectures to soil compaction was more sensitive in Zhengdan958 than Denghai605. Zhengdan958 showed greater growth performance than Denghai605 under noncompacted conditions, and the drought tolerance of Zhengdan958 was greater than that of Denghai605.